Apparatus for multiple completion wells



1965 J. w. DAUGHTREY APPARATUS FOR MULTIPLE COMPLETION WELLS 3 Sheets-Sheet 1 Filed Aug. 22, 1961 INVENTOR J'ase p Kid zoyire y B Y Mot ATTORNEY Dec. 28, 1965 J. w. DAUGHTREY 3,226,143

APPARATUS FOR MULTIPLE COMPLETION WELLS Filed Aug. 22, 1961 3 Sheets-Sheet 2 ATTORNEY.

Dec. 28, 1965 J. w. DAUGHTREY APPARATUS FOR MULTIPLE COMPLETION WELLS 3 Sheets-Sheet 3 Filed Aug. 22, 1961 //VV/V 7'01? JOSEPH DAUGI/TIQEV 5) C) ATTORNEY.

United States Patent 3,226,143 APPARATUS FDR MULTIPLE COMPLETION WELLS Joseph W. Daughtrey, Beaumont, Tex., assignor to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 22, 1961, Ser. No. 133,131 2 Claims. (Cl. 287-111) This invention relates to the completion of wells and more particularly to an apparatus for completing oil and/or gas wells having more than one producing horizon.

A recent trend in well completions is the cementing of multiple strings of tubing in one borehole. It is known in the field of well completion that production from two or more vertically displaced horizons can be accomplished simultaneously by cementing into a well two or more nonconcentric tubing strings, that may or may not terminate at different levels in an uncased borehole corresponding to these productive horizons, and producing each string of tubing independently of the others.

Well completion in the manner described above is usually accomplished by lowering a plurality of tubing strings into the well, isolating the various productive strata by means of packers or by means of cement retainers and/ or a column of cement, and thereafter producing the well through the individual tubing strings. The prior art methods, while effective in some cases, have several inherent disadvantages which are overcome by the present invention.

A principal disadvantage of the prior art methods is that it is extremely difficult to effect a primary cement job that will reliably locate a multiple tubing system within a borehole in such a way that communication between the various producing levels will be prevented. Another disadvantage of the prior art is that no reliable means are provided for controlled location and separation of the individual strings of tubing within the borehole. A further disadvantage of the prior art is that for Wells with more than two productive horizons, handling of pipe at the wellhead is unwieldy. These and numerous other disadvantages are not present when the apparatus of this invention is employed in a multiple completion well.

Thus, a fundamental object of this inveniton is to provide for the success of primary cement jobs in multiple casingless well completions.

It is another object of this invention to provide a method of completing Wells traversing more than one producing horizon whereby communication between the several horizons is prevented.

It is yet another object of this invention to provide apparatus for use in completing wells traversing more than one productive horizon.

It is still another object of this invention to provide controlled, equidistant separation of a plurality of tubing strings in nonconcentric arrangement in a borehole.

A further object of this invention is to provide a means for centralizing a multiple tubing system within a borehole.

Other objects, advantages, features and results and a more complete understanding of this invention may be had by referring to the detailed description and claims which follow when read in connection with the accompanying drawings, in which:

FIGURE 1 is a vertical cross-sectional view of a well completion illustrating a typical form and application of the present invention.

FIGURE 2 is a transverse sectional view on an enlarged scale taken along the line II-II of FIGURE 1 in the direction of the arrows.

FIGURE 3 is a transverse sectional view on an enlarged scale taken along the line IIIIII of FIGURE 1 in the direction of the arrows.

FIGURE 4 is a transverse sectional view of another embodiment of this invention.

FIGURE 5 is a view of one embodiment of the connecting components which make up the structure shown in FIGURE 1.

FIGURE 6 is a view of another embodiment of the connecting components which make up the structure shown in FIGURE 1.

FIGURE 7 is a view of yet another embodiment of the connecting components which make up the structure shown in FIGURE 1.

FIGURE 8 is a side view detailing a portion of the structure shown in FIGURE 1.

The apparatus of this invention is designed to accomplish the objects set out hereinbefore.

The clamping collars are construced to provide for rigid, equidistant spacing about an axis of a plurality of tubular conduits in nonconcentric arrangement in a borehole. Such control will enable a cement sheath to form around each individual tubing string during a cementing operation thus aiding in the isolation of the several productive horizons.

The centralizing means are designed to bear against the Walls of the borehole thereby tending to press and hold the tubing system defined by the clamping collars away from the uncased wall of borehole. This insures deposition of a uniform annulus of cement around the tubing system thus further aiding in the isolation of the several productive horizons.

In normal drilling, as mud i circulated through the well by rotary method it builds up a thin, relatively impermeable mud cake on the walls of the borehole. During a cementing operation the chemical and colloidal makeup of this mud cake is very often not conductive to a proper bond between the cement and the side of the hole. To eliminate this problem, the apparatus of this invention is provided with whisker-like abrasion wires which will scratch the mud and other obstructions from the borehole Wall to permit a successful bond between the cement column and the earth formations thus exposed in the borehole. In operation, after the tubing system has been positioned in the hole, the entire system is reciprocated to allow the scratchers to abrade the borehole walls.

From the foregoing brief description it is readily seen that the apparatus of this invention is designed to facilitate successful primary cement jobs in multiple casingless well completions, thereby providing a reliable and efficient means for completing wells traversing several productive horizons.

Referring now to FIGURE 1 which shows a preferred embodiment of this invention, a borehole 3 has been drilled through three vertically displaced productive horizons represented by A, B and C. A tubing system comprising three strings of production tubing 5, 5', 5" has been placed in the borehole in accordance with the method hereinafter described, one string of tubing terminating at the base of productive horizon C, one string of tubing terminating at the base of productive horizon B, and one string of tubing terminating at the base of productive horizon A. At selected intervals this tubing system 5, 5, 5", or a part thereof, is rigidly spaced and centralized by a pair of axially spaced annular clamping collars 1, hereinafter more fully described, illustrated in FIGURE 1 positioned at each end of a centralizing member 2. The centralizing member 2 comprises a plurality of outwardly bowed leaf spring components that are attached at their ends to one of two centralizer spring retaining rings 2a. The purpose of these centralizing members has been discussed hereinbefore. Scratchers 4, consisting of whiskerlike abrasion wires, are attached to clamping collar 1 in a conventional manner, such as that described in US. Patent No. 2,735,495 of Hall, Sr., issued February 21, 1956, US. Patent No. 2,685,931 of Baker et al., issued August 10, 1954, or US. Patent No. 2,628,682 of Wright, issued February 17, 1953. Scratchers 4 are circumferentially disposed around clamping collars 1 for the purpose hereinbefore mentioned. Several of these centralizing means will be utilized in a single well completion. The intervals at which the apparatus will be located along the tubing system will vary according to completion conditions such as number of tubing strings in the system, length and diameter of the individual tubing strings, diameter of the borehole, etc.

Considering now, in detail, the structure of the annular clamping collar which provides rigid, equidistant spacing of the tubing strings about an axis, reference is had to FIGURES 5, 6 and 7 which show three embodiments of the connecting components which make up the clamping collar.

Referring to FIGURE 5, the component shown includes outer member 10 having integral hinging means 11 on one end with cut-out portion 12 adapted to receive a cooperating hinging means from an adjacent connecting component. Hinging means 11 constitute a hinge barrel which is adapted to receive hinging pin 13, thereby pivotally attaching adjacent connecting components. The other end of outer member 10 has been formed into the female member of the clamping collar locking means. The shape of outer member 10 is defined by the shape of inner member 14 which comprises two arcuate elements 15 joined together by vertical member 16 which is welded in the position shown. Slim 17 are saw-toothed projections welded in the arcuate recess defined by elements 15 to prevent vertical movement of the tubing within the clamping collar. Inner member 14 is welded to outer member 10. The diameter of arcuate elements 15 is determined by the diameter of the tubing strings which they will partially encircle. Preferably, the tubing strings should fit into the arcuate recesses defined by arcuate elements 15 so that when the clamping collar is hammered closed: (a) slips 17 will set firmly against the tubing to prevent the tubing from slipping within the clamp as it is reciprocated in the borehole, and (b) the tubing string will set to the rear of the arcuate recess, thereby allowing the arcuate elements 15 of inner member 14 to partially encircle and lock the tubing in position and prevent its lateral movement toward the center of the opening defined by the annular clamping collar.

FIGURE 6 shows another embodiment of the connecting components which make up the clamping collar. The structure is similar to that of FIGURE except that it provides a male member of the clamping collar locking means.

FIGURE 7 shows an embodiment of one of the connecting components which is used in clamping tubing systems comprising three or more strings of tubing. The structure is similar to that of FIGURE 5 except that both ends of outer member have integral hinging means. One end is as shown in FIGURE 5 with integral hinging means 11 separated by cut-out portion 12. The other end of outer member 10 has been formed into a single integral hinging means 11 designed to be received by the cut-out portion 12 of an adjacent connecting component and pivotally attached thereto by means of pin 13.

From a consideration of FIGURES 2, 3 and 4 taken in connection with the foregoing description, it is readily seen that the number of double-hinge components shown in FIGURE 7 needed for a clamped tubular system will depend on the number of tubing strings in the system. 'For example, with the tubing system of FIGURE 2, where the opening formed by the clamping collar is roughly of bifoil section, the double-hinge component of FIGURE 7 is not needed; in FIGURE 3 where the opening formed by the clamping collar is roughly of trefoil section, one double-hinge component is needed; in FIGURE 4 where the opening formed by the clamping collar is roughly of quatrefoil section, two double-hinge components are needed; etc. FIGURES 3 and 4 also show van alternative hinging means 11a suitable for use with the apparatus of this invention. Hinging means 11a are not formed as continuous extensions of outer member 10 but comprise instead separate hinges that are joined to outer member 10 by welding, riveting, bolting or other suitable fastening means.

What has previously been designated as the male member of said locking means includes overlapping plate 23 which has been welded to one end of outer member 10. Extension 18 is adapted to be received by the cooperating female member of the clamping collar locking means. The female member includes cut-out projection 22 of outer member 10. "Slot 21 is designed to receive extension 18 of the male member.

Referring to FIGURE 8, in locking operation extension 18 is received into slot 21 of cut-out portion 22 and bent tab 19 struck from plate 23 engages opposing face 20 of the female member. To lock securely, bent tab 19 is hammered straight which causes it to bear against face 20 and thereby force end 24 of the outer member 10 of one of the components toward the end 25 of the outer member 10 of the other component thus setting the slips 17 to the tubing to form a rigidly clamped system.

Referring now to the method of completing a multiple production well in accordance with this invention, FIG- URE 1 shows a well drilled through three vertically displaced productive horizons A, B and C. After the well bore 3 has been drilled the tubing system comprising three strings of production tubing 5, 5' and 5" is lowered into the well bore in the following manner:

Tubing string 5 which will communicate with producing horizon C and terminate at the base thereof is lowered into the borehole a distance equal to the distance between the base of horizon C and the base of horizon B. Next tubing string 5" which will communicate with producing horizon B and terminate at the base thereof is lowered into the borehole.

Above the base of tubing string 5", the system formed by tubing strings 5 and 5" is rigidly clamped by the apparatus of this invention more fully described hereinbefore. The tubing strings are thereby positioned and secured equidistant from one another about a central axis as shown in cross section of FIGURE 2. Centralizing means 2 will bear against the walls of the borehole thus maintaining the system away from the walls of the borehole as the system is lowered therein.

The tubing system comprising 5 and 5" thus centrally located within the borehole is lowered into the well a disstan-ce equal to the distance between the base of horizon B and the base of horizon A. At this point tubing string 5 which will communicate with producing horizon A and terminate at the base thereof is associated with the tubing system.

Above the base of tubing string 5', tubing strings 5, 5 and 5 are rigidly positioned and secured equidistantly about a central axis by the apparatus of this invention as shown in cross section in FIGURE 3.

The tubing system comprising 5, 5 and 5" is then lowered into the well. The clamping and centralizing apparatus hereinbefore described is utilized to position and secure the tubing strings in place at various intervals as the system is lowered into the well. The intervals at which the system is so clamped will be determined by borehole condition, number of tubing strings in the system, etc.

When the tubing system is located at the desired level, i.e., tubing string 5 terminating at the base of horizon C, tubing string 5" terminating at the base of horizon B, et-c., the entire system is reciprocated several times so that the borehole walls are abraded by the scratcher Wires hereinbefore described. The Walls thus abraded are conductive to a better bond during a cementing operation.

Next, cement is pumped into the well bore through one or more of the tubing strings to form cement column 6. Due to the spacing of the tubing strings in the borehole, a cement sheath is able to form around each of the tubing strings thus providing for effective isolation of the various producing horizons and preventing communication therebetween. The level to which the cement column rises in the borehole will depend on borehole conditions such as degree of consolidation of formaiton traversed, number of tubing string in the system, etc.

Following the cementing operation each string of tubing may be perforated and produced independently of the others.

It is to be noted that the foregoing disclosure is merely an illustration of completion in accordance with this invention. The apparatus of this invention can be modified within the scope of this invention for use in wells having more than three producing horizons as evidenced by FIGURE 4 which shows a cross-sectional view of a completion system in which four strings of production tubing are equidistantly spaced about a central axis or limited to a dual completion well with tubing strings arranged in accordance with FIGURE 2.

Also, the foregoing description is not meant to limit in any way the level at which the various strings of tubing will terminate in the borehole, i.e., a string of tubing need not terminate at the base of a productive horizon but may terminate at any point above, opposite, or below the producing horizon with which it will communicate.

As previously mentioned, the length of the column of cement emplaced in the borehole will vary according to conditions mentioned hereinbefore, but generally it will extend at least from the base of the uppermost producing horizon to the top of the lowermost producing horizon.

From the foregoing it is apparent that the apparatus disclosed provides for accomplishment of the objects hereinbefore set forth. Variations and modifications apparent to one skilled in the art and within the scope of the claims which follow are expressly reserved.

I claim:

1. A collar for positioning and securing together a plurality of strings of tubing for cementing in a well comprising a plurality of components .pivotally attached end to end in a series to form a string of components having two free ends; the number of said components comprising the collar being equal to the number of tubing strings secured thereby; each component including an inner member having two juxtapositioned arcuate elements adapted to partially encircle tubing strings and a rigid outer member fitting over and secured to the outer surface of each of the arcuate elements, said outer member having a substantially straight central portion tangent to the arcuate elements; serrated gripping means extending inwardly from the inner surfaces of the arcuate elements; and locking means engaging the free ends of the string of components for drawing the free ends of the string of components together to tighten the components around the tubing strings.

2. A collar as set forth in claim 1 in which said locking means comprise a projection extending radially outward from the outer member of the component at one end of the string, a slot in said projection, an opening in the outer member from which the projection extends between the projection and the free end of said outer member, a plate secured to the outer surface of the outer member of the component at the other end of the string, an extension protruding from the end of the plate positioned to fit in the slot in the projection, and a tab struck from the plate ex tending outwardly from the plate and bent back toward the plate to place the free end of the tab in engagement with the edge of the opening remote from the projection when said extension is positioned in said slot whereby on flattening the tab the collar is tightened.

References Cited by the Examiner UNITED STATES PATENTS 1,821,234 9/1931 Parker 138-112 2,297,146 9/1942 Guirl 138-112 2,845,128 7/1958 Clark et al 166-241 2,986,415 5/1961 Park 287-52 2,994,382 8/1961 OReilly 166-241 2,998,848 9/1961 Wright et al. 166-241 3,108,639 10/1963 Brooks 166-241 OTHER REFERENCES Humble Has New Completion Method: The Oil and Gas Journal, Nov. 17, 1958; vol. 56, No. 46, pp. 136 and 137.

CHARLES E. OCONNELL, Primary Examiner. 

1. A COLLAR FOR POSITIONING AND SECURING TOGETHER A PLURALITY OF STRINGS OF TUBING FOR CEMENTING IN A WELL COMPRISING A PLURALITY OF COMPONENTS PIVOTALLY ATTACHED END TO END IN A SERIES TO FORM A STRING OF COMPONENTS HAVNG TWO FREE ENDS; THE NUMBER OF SAID COMPONENTS COMPRISING THE COLLAR BEING EQUAL TO THE NUMBER OF TUBING STRAINS SECURED THEREBY; EACH COMPONENT INCLUDING AN INNER MEMBER HAVING TWO JUXTAPOSITIONED ARCUATE ELEMENTS ADAPTED TO PARTIALLY ENCIRCLE TUBING STRINGS AND A RIGID OUTER MEMBER FITTING OVER AND SECURED TO THE OUTER SURFACE OF EACH OF THE ARCUATE ELEMENTS, SADI OUTER MEMBER HAVING A SUBSTANTIALLY STRAIGHT CENTRAL PORTION TANGENTTO THE ARCUATE ELEMENTS; SERRATED GRIPPING MEANS EXTENDING INWARDLY FROM THE INNER SURFACES OF THE ARCUATE ELEMENT; AND LOCKING MEANS ENGAGING THE FREE ENDS OF THE STRING OF COMPONENTS FOR DRAWING THE FREE ENDS OF THE STRING OF COMPONENTS TOGETHER TO TIGHTEN THE COMPONENTS AROUND THE TUBING STRINGS. 